Emulation system for a motor vehicle drivetrain

Patent · Tue Jul 21 04:00:00 EDT 1987

OSTI ID:6232757

Henry, K J; Kotwicki, A J

This patent describes a motor vehicle engine testing arrangement including a motor vehicle engine and an electric dynamometer coupled to the output shaft of such engine and adapted to regulate the engine speed in accordance with a speed control signal applied. A method is described of operating the dynamometer to emulate the combined effect of a motor vehicle and conventional motor vehicle drivetrain elements including a fluidic torque converter and a shiftable ratio automatic transmission, such method comprising the steps of: defining first and second differential equations relating to the ability of the drivetrain input torque to accelerate the engine inertia, and the ability of the drivetrain output torque to overcome the road load and accelerate the vehicle inertia; modeling the combined operation of a fluidic torque converter and a shiftable ratio automatic transmission, and coupling the first and second differential equations so the drivetrain input torque is determined as a function of measured engine output torque and the load that would be imposed on the engine by the torque converter. The drivetrain output torque is determined as a function of the transmission output torque and the road load of the vehicle; periodically integrating the first and second differential equations forward in time assuming substantially constant engine output torque during the integration period to predict the engine speed that would occur were the engine driving a motor vehicle through the defined drivetrain elements in opposition to the road load; and generating a speed control signal for the dynamometer in accordance with the predicted engine speed to load the engine as though it were actually installed in a motor vehicle with the modeled drivetrain elements.

• Assignee: General Motors Corp., Detroit, MI
• Patent Number(s): US 4680959
• OSTI ID: 6232757
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330602* -- Vehicle Design Factors-- Engine-Transmission Matching
ACCELERATION
COMPUTER CALCULATIONS
COMPUTERIZED CONTROL SYSTEMS
CONTROL EQUIPMENT
CONTROL SYSTEMS
DIFFERENTIAL EQUATIONS
DYNAMOMETERS
ENGINES
EQUATIONS
EQUIPMENT
MACHINE PARTS
MEASURING INSTRUMENTS
MECHANICAL TRANSMISSIONS
MOMENT OF INERTIA
PERFORMANCE TESTING
SIGNALS
SPEED REGULATORS
TESTING
TORQUE
VEHICLES
VELOCITY